Look at this series: 7, 10, 8, 11, 9, 12, . . . What number should come next? - Number Series - Seri

In following number series, two terms have been put within brackets. Choose the appropriate option - Look at this series: 7, 10, 8, 11, 9, 12, . . . What number should come next?

A. 7

B. 10

C. 12

D. 13

E. None of the above

Answer: B. 10

This is a simple alternating addition and subtraction series.
In the first pattern, 3 is added;
In the second pattern, 2 is subtracted.

Rule =(1st number) (1st number + 3 = 2nd number) (2nd number - 2 = 3rd number) (3rd number + 3 = 4th number)
Now (7) (7 + 3 = 10) (10 - 2 = 8) (8 + 3 = 11) (11 - 2 = 9) (9 + 3 = 12) (12 - 2 = 10)...
So the answer is b = 10.

Posted in: Number Series - Series Completion - Verbal Reasoning